1. Field of the Invention
The present invention relates to a cuff for a blood pressure monitor and, more particularly, to a cuff characterized by a curled elastic member disposed on the outside of a bladder to hold a ring form of the cuff.
2. Description of the Related Art
As shown in FIG. 11 (perspective view) and FIG. 12 (sectional view), a cuff for a blood pressure monitor has generally a configuration such that a bladder 91 and a curled elastic member 92 are provided in a cloth bag 90. A tube 93 is connected to the bladder 91, and a velcro fastener 94 is attached on the outside of the cloth bag 90. The curled elastic member 92 is disposed on the outside of the bladder 91 to hold the cuff in a ring form by its elasticity. As shown in FIG. 13A, the curled elastic member 92 has an uniform thickness and has a sectional shape of a complete round in which a part thereof is a discontinuous portion 92a. 
However, the curled elastic member 92 as shown in FIG. 13A has the following problems 1 to 3.
1. Operation of uncurling the curled elastic member 92 to be attached on an arm is not easy.
Since the sectional shape is a complete round, the curled elastic member 92 has to be uncurled and then attached on an arm. Specifically, in order to uncurl the curled elastic member 92, it has to be pulled with some strength. The user needs some experience to attach the elastic member 92 in the uncurled state onto his/her arm.
2. When the curled elastic member 92 is attached around an arm, the edges of the discontinuous portion 92a of the curled elastic member cut into the flesh of the arm due to its elastic force so that users in particular with thick arm often feel pain.
3. Since the curled elastic member 92 has uniform thickness and the sectional shape thereof is complete round, it cannot deform so as to correspond to a person with thick arm or a person with thin arm and hence is difficult to fit such arms.
For addressing the above described problems, Japanese Laid-open Patent Publication No. S61-238229 (1986) proposes a curled elastic member 92′ as shown in FIG. 13B. This curled elastic member 92′ is so configured that its thickness gradually increases in a circumferential direction of an arm from the both ends toward the center portion. Hence the rigidity of the curled elastic member 42 gradually increases. The thickness and rigidity are the maximum at the center portion.
This curled elastic member 92′ has somewhat solved the aforementioned problems. However, for an arm whose diameter changes to a large extent depending on the part of the arm, in other words, for a largely-inclined arm, such as an upper arm whose diameter is small in the vicinity of the elbow but gradually increases toward the shoulder, the curled elastic member 92′ fits the large diameter part of the arm while leaving a clearance with respect to the small diameter part of the arm. As described above, the curled elastic member 92′ cannot sufficiently deform to correspond to the shape of the arm.
The present invention is directed to solving the above-mentioned problems associated with conventional cuffs for a blood pressure monitor. It is an object of the present invention to provide a cuff for a blood pressure monitor with excellent fitting ability which can fit various shapes of arms, in particular, largely-inclined arms.